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Diffstat (limited to 'subprojects/store-reasoning-scope/src/main/java/tools/refinery/store/reasoning/scope/BoundScopePropagator.java')
-rw-r--r-- | subprojects/store-reasoning-scope/src/main/java/tools/refinery/store/reasoning/scope/BoundScopePropagator.java | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/subprojects/store-reasoning-scope/src/main/java/tools/refinery/store/reasoning/scope/BoundScopePropagator.java b/subprojects/store-reasoning-scope/src/main/java/tools/refinery/store/reasoning/scope/BoundScopePropagator.java new file mode 100644 index 00000000..62aadb4a --- /dev/null +++ b/subprojects/store-reasoning-scope/src/main/java/tools/refinery/store/reasoning/scope/BoundScopePropagator.java | |||
@@ -0,0 +1,229 @@ | |||
1 | /* | ||
2 | * SPDX-FileCopyrightText: 2023 The Refinery Authors <https://refinery.tools/> | ||
3 | * | ||
4 | * SPDX-License-Identifier: EPL-2.0 | ||
5 | */ | ||
6 | package tools.refinery.store.reasoning.scope; | ||
7 | |||
8 | import com.google.ortools.linearsolver.MPConstraint; | ||
9 | import com.google.ortools.linearsolver.MPObjective; | ||
10 | import com.google.ortools.linearsolver.MPSolver; | ||
11 | import com.google.ortools.linearsolver.MPVariable; | ||
12 | import org.eclipse.collections.api.factory.primitive.IntObjectMaps; | ||
13 | import org.eclipse.collections.api.factory.primitive.IntSets; | ||
14 | import org.eclipse.collections.api.map.primitive.MutableIntObjectMap; | ||
15 | import org.eclipse.collections.api.set.primitive.MutableIntSet; | ||
16 | import tools.refinery.store.dse.propagation.BoundPropagator; | ||
17 | import tools.refinery.store.dse.propagation.PropagationResult; | ||
18 | import tools.refinery.store.model.Interpretation; | ||
19 | import tools.refinery.store.model.Model; | ||
20 | import tools.refinery.store.query.ModelQueryAdapter; | ||
21 | import tools.refinery.store.representation.cardinality.*; | ||
22 | import tools.refinery.store.tuple.Tuple; | ||
23 | |||
24 | class BoundScopePropagator implements BoundPropagator { | ||
25 | private final ModelQueryAdapter queryEngine; | ||
26 | private final Interpretation<CardinalityInterval> countInterpretation; | ||
27 | private final MPSolver solver; | ||
28 | private final MPObjective objective; | ||
29 | private final MutableIntObjectMap<MPVariable> variables = IntObjectMaps.mutable.empty(); | ||
30 | private final MutableIntSet activeVariables = IntSets.mutable.empty(); | ||
31 | private final TypeScopePropagator[] propagators; | ||
32 | private boolean changed = true; | ||
33 | |||
34 | public BoundScopePropagator(Model model, ScopePropagator storeAdapter) { | ||
35 | queryEngine = model.getAdapter(ModelQueryAdapter.class); | ||
36 | countInterpretation = model.getInterpretation(storeAdapter.getCountSymbol()); | ||
37 | solver = MPSolver.createSolver("GLOP"); | ||
38 | objective = solver.objective(); | ||
39 | initializeVariables(); | ||
40 | countInterpretation.addListener(this::countChanged, true); | ||
41 | var propagatorFactories = storeAdapter.getTypeScopePropagatorFactories(); | ||
42 | propagators = new TypeScopePropagator[propagatorFactories.size()]; | ||
43 | for (int i = 0; i < propagators.length; i++) { | ||
44 | propagators[i] = propagatorFactories.get(i).createPropagator(this); | ||
45 | } | ||
46 | } | ||
47 | |||
48 | ModelQueryAdapter getQueryEngine() { | ||
49 | return queryEngine; | ||
50 | } | ||
51 | |||
52 | private void initializeVariables() { | ||
53 | var cursor = countInterpretation.getAll(); | ||
54 | while (cursor.move()) { | ||
55 | var interval = cursor.getValue(); | ||
56 | if (!interval.equals(CardinalityIntervals.ONE)) { | ||
57 | int nodeId = cursor.getKey().get(0); | ||
58 | createVariable(nodeId, interval); | ||
59 | activeVariables.add(nodeId); | ||
60 | } | ||
61 | } | ||
62 | } | ||
63 | |||
64 | private MPVariable createVariable(int nodeId, CardinalityInterval interval) { | ||
65 | double lowerBound = interval.lowerBound(); | ||
66 | double upperBound = getUpperBound(interval); | ||
67 | var variable = solver.makeNumVar(lowerBound, upperBound, "x" + nodeId); | ||
68 | variables.put(nodeId, variable); | ||
69 | return variable; | ||
70 | } | ||
71 | |||
72 | private void countChanged(Tuple key, CardinalityInterval fromValue, CardinalityInterval toValue, | ||
73 | boolean ignoredRestoring) { | ||
74 | int nodeId = key.get(0); | ||
75 | if ((toValue == null || toValue.equals(CardinalityIntervals.ONE))) { | ||
76 | if (fromValue != null && !fromValue.equals(CardinalityIntervals.ONE)) { | ||
77 | removeActiveVariable(toValue, nodeId); | ||
78 | } | ||
79 | return; | ||
80 | } | ||
81 | if (fromValue == null || fromValue.equals(CardinalityIntervals.ONE)) { | ||
82 | activeVariables.add(nodeId); | ||
83 | } | ||
84 | var variable = variables.get(nodeId); | ||
85 | if (variable == null) { | ||
86 | createVariable(nodeId, toValue); | ||
87 | markAsChanged(); | ||
88 | return; | ||
89 | } | ||
90 | double lowerBound = toValue.lowerBound(); | ||
91 | double upperBound = getUpperBound(toValue); | ||
92 | if (variable.lb() != lowerBound) { | ||
93 | variable.setLb(lowerBound); | ||
94 | markAsChanged(); | ||
95 | } | ||
96 | if (variable.ub() != upperBound) { | ||
97 | variable.setUb(upperBound); | ||
98 | markAsChanged(); | ||
99 | } | ||
100 | } | ||
101 | |||
102 | private void removeActiveVariable(CardinalityInterval toValue, int nodeId) { | ||
103 | var variable = variables.get(nodeId); | ||
104 | if (variable == null || !activeVariables.remove(nodeId)) { | ||
105 | throw new AssertionError("Variable not active: " + nodeId); | ||
106 | } | ||
107 | if (toValue == null) { | ||
108 | variable.setBounds(0, 0); | ||
109 | } else { | ||
110 | // Until queries are flushed and the constraints can be properly updated, | ||
111 | // the variable corresponding to the (previous) multi-object has to stand in for a single object. | ||
112 | variable.setBounds(1, 1); | ||
113 | } | ||
114 | markAsChanged(); | ||
115 | } | ||
116 | |||
117 | MPConstraint makeConstraint() { | ||
118 | return solver.makeConstraint(); | ||
119 | } | ||
120 | |||
121 | MPVariable getVariable(int nodeId) { | ||
122 | var variable = variables.get(nodeId); | ||
123 | if (variable != null) { | ||
124 | return variable; | ||
125 | } | ||
126 | var interval = countInterpretation.get(Tuple.of(nodeId)); | ||
127 | if (interval == null || interval.equals(CardinalityIntervals.ONE)) { | ||
128 | interval = CardinalityIntervals.NONE; | ||
129 | } else { | ||
130 | activeVariables.add(nodeId); | ||
131 | markAsChanged(); | ||
132 | } | ||
133 | return createVariable(nodeId, interval); | ||
134 | } | ||
135 | |||
136 | void markAsChanged() { | ||
137 | changed = true; | ||
138 | } | ||
139 | |||
140 | @Override | ||
141 | public PropagationResult propagateOne() { | ||
142 | queryEngine.flushChanges(); | ||
143 | if (!changed) { | ||
144 | return PropagationResult.UNCHANGED; | ||
145 | } | ||
146 | changed = false; | ||
147 | for (var propagator : propagators) { | ||
148 | propagator.updateBounds(); | ||
149 | } | ||
150 | var result = PropagationResult.UNCHANGED; | ||
151 | if (activeVariables.isEmpty()) { | ||
152 | return checkEmptiness(); | ||
153 | } | ||
154 | var iterator = activeVariables.intIterator(); | ||
155 | while (iterator.hasNext()) { | ||
156 | int nodeId = iterator.next(); | ||
157 | var variable = variables.get(nodeId); | ||
158 | if (variable == null) { | ||
159 | throw new AssertionError("Missing active variable: " + nodeId); | ||
160 | } | ||
161 | result = result.andThen(propagateNode(nodeId, variable)); | ||
162 | if (result.isRejected()) { | ||
163 | return result; | ||
164 | } | ||
165 | } | ||
166 | return result; | ||
167 | } | ||
168 | |||
169 | private PropagationResult checkEmptiness() { | ||
170 | var emptinessCheckingResult = solver.solve(); | ||
171 | return switch (emptinessCheckingResult) { | ||
172 | case OPTIMAL, UNBOUNDED -> PropagationResult.UNCHANGED; | ||
173 | case INFEASIBLE -> PropagationResult.REJECTED; | ||
174 | default -> throw new IllegalStateException("Failed to check for consistency: " + emptinessCheckingResult); | ||
175 | }; | ||
176 | } | ||
177 | |||
178 | private PropagationResult propagateNode(int nodeId, MPVariable variable) { | ||
179 | objective.setCoefficient(variable, 1); | ||
180 | try { | ||
181 | objective.setMinimization(); | ||
182 | var minimizationResult = solver.solve(); | ||
183 | int lowerBound; | ||
184 | switch (minimizationResult) { | ||
185 | case OPTIMAL -> lowerBound = RoundingUtil.roundUp(objective.value()); | ||
186 | case UNBOUNDED -> lowerBound = 0; | ||
187 | case INFEASIBLE -> { | ||
188 | return PropagationResult.REJECTED; | ||
189 | } | ||
190 | default -> throw new IllegalStateException("Failed to solve for minimum of %s: %s" | ||
191 | .formatted(variable, minimizationResult)); | ||
192 | } | ||
193 | |||
194 | objective.setMaximization(); | ||
195 | var maximizationResult = solver.solve(); | ||
196 | UpperCardinality upperBound; | ||
197 | switch (maximizationResult) { | ||
198 | case OPTIMAL -> upperBound = UpperCardinalities.atMost(RoundingUtil.roundDown(objective.value())); | ||
199 | // Problem was feasible when minimizing, the only possible source of {@code UNBOUNDED_OR_INFEASIBLE} is | ||
200 | // an unbounded maximization problem. See https://github.com/google/or-tools/issues/3319 | ||
201 | case UNBOUNDED, INFEASIBLE -> upperBound = UpperCardinalities.UNBOUNDED; | ||
202 | default -> throw new IllegalStateException("Failed to solve for maximum of %s: %s" | ||
203 | .formatted(variable, minimizationResult)); | ||
204 | } | ||
205 | |||
206 | var newInterval = CardinalityIntervals.between(lowerBound, upperBound); | ||
207 | var oldInterval = countInterpretation.put(Tuple.of(nodeId), newInterval); | ||
208 | if (newInterval.lowerBound() < oldInterval.lowerBound() || | ||
209 | newInterval.upperBound().compareTo(oldInterval.upperBound()) > 0) { | ||
210 | throw new IllegalArgumentException("Failed to refine multiplicity %s of node %d to %s" | ||
211 | .formatted(oldInterval, nodeId, newInterval)); | ||
212 | } | ||
213 | return newInterval.equals(oldInterval) ? PropagationResult.UNCHANGED : PropagationResult.PROPAGATED; | ||
214 | } finally { | ||
215 | objective.setCoefficient(variable, 0); | ||
216 | } | ||
217 | } | ||
218 | |||
219 | private static double getUpperBound(CardinalityInterval interval) { | ||
220 | var upperBound = interval.upperBound(); | ||
221 | if (upperBound instanceof FiniteUpperCardinality finiteUpperCardinality) { | ||
222 | return finiteUpperCardinality.finiteUpperBound(); | ||
223 | } else if (upperBound instanceof UnboundedUpperCardinality) { | ||
224 | return Double.POSITIVE_INFINITY; | ||
225 | } else { | ||
226 | throw new IllegalArgumentException("Unknown upper bound: " + upperBound); | ||
227 | } | ||
228 | } | ||
229 | } | ||